Addition agents for mineral oil lubricants



Patented'June 7, 1949 ADDITION AGENTS FOR MINERAL OIL LUBRICANTS Troy L. Cantrell, Lansdowne, and Herschel G.

Smith, Wallinglord, Pa.,

assignors to Gulf Oil Corporation, Pittsburgh, Pa., a corporation of Pennsylvania No Drawing. Application June 20, 1947, Serial No. 756,090

22 Claims. '(cl. 252-423) This invention relates to addition agents'for mineral oil lubricants, and more particularly, it

relates to addition agents which confer improved bearing-corrosion-inmbiting and-detergent propertes on mineral oil lubricants.

In the lubrication ofinternal combustion engines of all types, particularly when severe operating conditions-are encountered, mineral lubricating oils frequently'prove unsatisfactory because they tend to deposit varnish, gum and sludge on the engine surfaces, such as the cylinder walls, pistons and rings, and also to induce corrosion of bearing materials. These problems have become increasingly serious because of the trend toward higher efliciency or higher power in conditions tending to accelerate deteriorating influences on the mineral oil lubricant.

The formation of so-called varnishes and sludges on engine surfaces is a result of oxidation effects on the lubricating oils. The presence of such engine deposits is detrimental for many reasons. These substances increase ring sticking and accelerate the formation of further deposits on piston surfaces and fixed part of the I combustion chamber. The sludges formed in the crank case of the engine increase the rate of corrosion of bearing surfaces, especially of bearing alloys of the type now in use.

In the lubrication of steam turbines, the problems become more acute because of the presence of water in the mineral oil lubricant. Therefore, in addition to bearing corrosion, rusting may also be encountered.

, It is an object of this invention, therefore, to provide an addition agent for mineral oil lubricants which will prevent the formation of the engine deposits encountered in the use of mineral for mineral oil lubricants, there is provided a salt having the following formula:

M o 0 on on I l l I CUr'UCHr-OSO l I l R R R R wherein R is an alkyl radical having from 4 to 12 carbon atoms, and M is a divalent metal. The

output per unit weight of engine, which results above salts are excellent detergents and in most instances are remarkably efiective also for inhibiting bearing corrosion and rusting in the use of mineral oil lubricants. Such salts, as well as the mineral oil lubricant compositions containing them, are believed to be novel and are considered part of our invention.

The salts of our invention are prepared by condensing one mol of a divalent metal salt of a phenol having a para alkyl substitutent of from 4 to 12 carbon atoms, two mols of formaldehyde, and one mol of a phenol sulfide obtained by reacting two mols of a phenol having a para alkyl substituent of from 4 to 12 carbon atoms with one mol of sulfur dichloride (SClz) The divalent metal salts of the alkylated phenols used in preparing the addition agents of our invention are conveniently made by neutralizing the alkylated phenol with an oxide or hydroxide ofthe particular divalent metal desired. Alternatively, the alkali metal phenate of the phenol may first be made, and then the phenate may be reacted with a water-soluble salt of the divalent metal to yield the divalent metal salt of the phenol by a double decomposition reaction.

The phenol sulfide used in making our new addition agents is prepared by reacting two mols of a para alkyl phenol with one mol of sulfur dichloride according to the reaction.

on on nu O S h O-S-O 2HCI I I I R R R The reaction of the sulfur dichloride with the alkylated phenol may take place at room temperature, and it usually is preferred to initiate the reaction at such temperature and then to raise the temperature to no higher than 350 F. to complete the reaction. However, the reaction may take place at any temperature ranging from room temperature to 350 F., provided care is taken that the latter temperature is not exceeded. If the temperature of 350 F. is exceeded to any great extent, especially in the initial stages of the reaction, the product formed tends to be dark-colored and transmits to our new addition agents an undesirable dark-color and a tendency to be insoluble in mineral lubricating oils. The reaction of the para alkyl phenol with the sulfur dichloride may take place in the presence of an inert solvent, such as benzene, toluene. hexane, carbon tetrachloride, chloroform, cyclohexane, etc., to obtain a lighter-colored product. Also, the resulting phenol sulfide may be treated with a decolorizing clay, such as acid treated bentonite and the like, in order to remove dark-colored byproducts.

The resulting phenol sulfide and the dilvalent metal salt of the para alkyl phenol are then condensed with formaldehyde in the proportions stated, with the splitting 05 of two male of water to yield our new addition agents. The condensation takes place upon heating, preferably to a temperature not greater than 275 F. In lieu of formaldehyde, formaldehyde-yielding compounds, such as trioxymethylene, paraformaldehyde and the like may be employed. Accordingly, as used in the appended claims, the term "formaldehyde is intended to include such formaldehyde-yielding substances, as well as formaldehyde itself.

The phenols used in preparing both the divalent metal salt of the para alkyl phenol and the phenol sulfide are para alkyl substituted phenols having from 4 to 12 carbon atoms in the alkyl substituent. Thus, the alkyl substituent may include normal or branched chain butyl, amyl, hexyl, heptyl, octyl, decyl and dodecyl radicals. A preferred alkyl substituent is the tetramethylbutyl radical. The para alkyl phenols are preferably obtained by alkylat ing in known manner, in the presence of concentrated sulfuric acid, phenol with olefins having from 4 to 12 carbon atoms. Olefins such as butene-l, isobutylene, the amylenes, di-isobutylene and triisobutylene may conveniently be employed. It is preferred to conduct the alkylation with di-isobutylene since the resulting product is primarily a para tetramethylbutyl phenol.

Any divalent metal may be used in forming the salt of the para alkyl phenol to yield excellent detergent compounds. Representative divalent metals include beryllium, calcium, barium, magnesium, strontium, zinc, stannous tin, copper, lead, cobalt and nickel. However, not all of the divalent metal salts of our invention confer bearing corrosion-inhibiting properties. Thus, copper and lead salts, although providing excellent detergent properties, are ordinarily not as useful as the other salts of our invention for inhibiting bearing corrosion. Accordingly, a preferred sub-group of the divalent metals is the alkaline earth metals, since the salts of these metals confer both detergent and corrosion-inhibiting properties. Stannous salts are also excellent for both purposes. However, all of the divalent metal salts of our invention are excellent detergent agents, and therefore will confer detergent properties on mineral oil lubricants.

If particular divalent metal salts which do not have bearing corrosion-inhibiting properties are used in mineral oil lubricants for their detergent effects, other materials, such as the calcium and barium salts of the present invention, or other known bearing corrosion inhibitors may be added to obtain the desired bearing corrosioninhibiting effect. The metal salts of our inven tion are also potent rust inhibitors, and act as mild extreme pressure agents.

The following examples further illustrate our invention: f

Example I.Into a first enamel lined jacketed reaction vessel were charged 188 pounds of phenol, 240 pounds of di-isobutylene, and 9 pounds of 96 per cent sulfuric acid catalyst. The vessel was then closed and the contents were agitated, while passing cooling water through the Jacket to prevent the reaction temperature from exceeding 220 F. The temperature was maintained at 220 F. for 12 hours. At the end of this period, a slurry of 84 pounds of hydrated lime in 150 pounds of water was added to the para tetramethylbutyl phenol formed in the reaction vessel, resulting in the formation of the substantially neutral calcium salt of the para tetramethylbutyl phenol.

To a second enamel lined jacketed reaction vessel, there were added 188 pounds of phenol, 240 pounds of di-isobutylene and 9 pounds of 96 per cent sulfuric acid, and the temperature was maintained at 220 F. for 12 hours. At the end of this period, the resulting para tetra methylbutyl phenol was cooled to 60 F. and diluted with 400 pounds of hexane. Then 102 pounds of sulfur dichloride were added over a period of 3 hours. The byproduct (anhydrous hydrogen chloride) was vented to a hydrochloric acid recovery plant. The temperature was then raised to 140 F., where it was held for 10 hours.

The contents of the first reaction vessel were then charged into and mixed with the contents of the second reaction vessel, and 162 pounds of 37 per cent aqueous formaldehyde were added.

The temperature was then raised to F. and held there for 4 hours. Then the mixture was allowed to settle, and the water layer was drawn off. The solvent layer was filtered through a continuous filter, and the filtrate distilled to remove the hexane solvent. The salt obtained had the following properties:

' Per cent Sulfur 3.44 Ash, as oxide 8.63

The salt had the following formula:

temperature was maintained at 220 F. for 12 hours. Of the resulting para tetramethylbutyl three hours.

hydrogen chloride was 4 iting properties.

sel, there was added. at a temperature of 130 F.,

1122 pounds of sulfur dichloride over a period of The temperature was then raised to 210 F. and held there for 18 hours. By-product vented to a hydrochloric acid recovery plant. phenol sulfide was then diluted with 5060 pounds of a light lubricating oil having the following properties:

Gravity, mm 30.4 Viscosity, SUV, 210 'F 43.5 Color, NPA 1.75

Neutralization No nil To the resulting solution, 920 pounds of a decolorizing clay were added, the mixture was agitated at 230 F. for 6 hours and then filtered through a continuous filter.

To the 3833 pounds of para tetramethylbutyl phenol in the second reactor,v there was added 4000 pounds of alight lubricating oil having identical properties with those shown above. and a consisting of the mineral oil solution of the al- The resulting alkylated 6 cient to eifect the desired'improvement. In view of their high molecular weight and low volatility at high temperatures, our new addition agents are particularly advantageous for preparing lubricantswhich encounter high temperatures, such as aviation lubricating oils. The following examples illustrate the use of our new addition agents to obtain improved mineral oil lubricant compositions.

Example IlI.An improved lubricating oil was prepared by blending a highly refined mineral lubricating oil with 1.0 per cent by weight of the l compound prepared in accordance with Exampie I. A comparison of the properties of the base oilqind improved oil follows:

Base Oil Improved Oil Gravity, API 25.9. Viscosity SUV:

100 f 1,588. v 2109 F 118. Viscosity Index. 98. Flash, 00. "r 535. Fire. 00, F 590.

kylated phenol sulfide, was then mixed with the contents of the second reaction vessel along with 1458 pounds of 37. per cent aqueous formaldehyde.

The mixture was agitated, heated. to.210 F1, and maintained at that temperature for 6 hours. Then the temperature was raised to 290 F. to remove all water. and to'dry the product. The dehydrated all solution of the reaction product was filtered through a continuous filter and had the following properties:

Gravity, API 16.6

Viscosity, SUV:

100 F 7493 210' F 159.6 Color, NPA (dil.) 2.5 Sulfur, B ..per cent" 1.! Neutralization No 0.5 Ash as oxide per cent 4.1

' which may then be diluted down to the proportion desired in the final mineral oil lubricant composition. As stated, our new addition agents confer excellent detergent effects, on the mineral lubricating oils with which they are incorporated,

. and in most instances confer in addition excellent bearing corrosion-inhibiting and rust-inhib- For these purposes, our new addition agents are generally added to mineral oils in minor amounts, say from 0.1 per cent to 10.0 per cent by weight of the mineral oil, 'suflicient to confer improved detergent propertieson' Y the mineral lubricating oils with which theyare incorporated. Generally, the addition of 1.0 per cent by weight of our new addition agents is sum- Corrosion Test,

Pour, "F Precipitation No Copper Strip Test, 212' F., 3 Hr AS'IM D665-46'l Distilled Water:

Steel Rod, Appearance Area Rusted, Per Cent Falex Wear Test:

510 Lb. Gauge Load, 15 Min.

Wear, No. of Teeth Gauge Load at Seizure, Lh.

bright. nil.

As shown in this example, the addition of our new agent inhibited rusting and alsoimproved the pressure-carrying properties.

Example lV.An improved lubricating oil was prepared by blending witha highly refined mineral lubricating oil 6 per cent by weight of the additive concentrate prepared in accordance with Example II. A comparison of the properties of he base oil and improved oil follows:

Base Oil Improved Oil Gravity, API 27.5. Viscosity, SUV:

210 F 07.8. Viscosity Index. 97. Flash, 00 F- 470. Fire, 00, 545. Pour, "F 5. c""%iiii1"ar'i" iii" opper pas, r passes. Corrosion Test, ASTM D665 461 Distilled Water:

Steel, Rod, tglppearanoefi rust bright. Area Rus Per Cent.. n'il. Centrifuge Test,.Separation, Per Cent: 1500 R. I. M., Room TomIp.2I-Ir nil nil. UV ight Stability Quartz Tube,8Hr.: Appearance bright bright. Chevrolet 36'Hr. Engine Test CRO Designation C-4: Enzine Rating failed to .eom- -29.

' pleto test.

As'shown in this example under the corrosion test, our new addition agents inhibit rusting. The remarkably effective detergent and bearing corrosion-inhibiting properties imparted to the A base oil are shown by the data on the Chevrolet 36 hour engine-test. In thehyphenated figures shown thereunder, the figure to the left of the hyphen indicates the freedom from engine deposits expressed in per cent, the larger the per cent (approaching as a limit) the cleaner the engine. The marked improvement in detergent efiects obtained from the use of our new addition agents is clear. The figure to the right of the hyphen indicates the amount of bearing corrosion expressed in milligrams loss in weight of a standard bearing. Our new addition agent clearly confers excellent bearing corrosion-inhibiting properties. Finally, the above data show the excellent stability and solubility of our new addition agents.

The Chevrolet 36 hour engine test referred to above is an accepted standard test designed to determine the oxidation, detergency and bearing corrosion characteristics of engine crank case oils designed for use under heavy duty service conditions. In this procedure, the crank case lubricant is evaluated with respect to its stability or resistance to oxidation, bearing corrosion and the deposition of contaminants resulting from decomposition and oxidation or other changes that occur in the lubricant in service. The procedure involves the intermittent operation of.a special fi-cylinder automotive test engine at constant speed and load for a total of 36 hours subsequent to a run-in period of 8 hours at graduated speeds and loads. Prior to each test, a complete set of new piston rings is installed and two new weighed copper-lead test bearings are installed in symmetrical location. Performance of the test 011 is judged by examination of the power section of the engine for deposits and by ascertaining the weight loss of the test bearings.

While we have shown in the above examples the preparation of compounded lubricating oils, our invention is not limited thereto, but comprises all mineral oil lubricant compositions containing our new addition agents, such as greases and the like.

We claim:

L A salt having the formula:

o on on O CD O O R R R I:

K 0 on on CH,- cm-QsU I R R n where R is the tetramethylbutyl radical.

8. The process which comprises condensing one mol of a divalent metal salt of a phenol having a para alkyl substituent of from 4 to 12 carbon atoms, two mols of formaldehyde, and one mol of a phenol sulfide obtained by reacting two mols of a phenol having a para alkyl substituent of from 4 to 12 carbon atoms with one mol of sulfur dichloride.

9. The process which comprises condensing at a temperature not greater than 275 F. one mol of a divalent metal salt of a phenol having a para alkyl substituent of from 4 to 12 carbon atoms, two mols of formaldehyde, and one mol of a phenol sulfide obtained by reacting at a temperature ranging from room temperature to 350 F. two mols of a phenol having a para alkyl substituent of from 4 to 12 carbon atoms with one mol of sulfur dichloride.

10. The process of claim 9, wherein the divalent metal salt is a calcium salt, and the para alkyl substituent of the phenol is the tetramethylbutyl radical.

11. A lubricant composition comprising a major amount of a mineral lubricating oil'and a minor amount, sufficient to confer detergent properties on the composition, of a salt having the formula:

M o on on l OOHUCH R R R wherein R is an alkyl radical having from 4 to 12 carbon atoms, and M is a divalent metal.

12. The composition of claim 11, wherein M is an alkaline earthmetal.

13. The composition of claim 11, wherein M is calcium.

14. The composition of claim 11, wherein M is barium.

15. The composition of claim 11, wherein M is tin.

16. The composition of claim 11, wherein R is the tetramethylbutyl radical.

17. The composition of claim 11, wherein the salt is present in an amount of from 0.1 to 10.0 per cent by weight on the mineral oil.

18; A lubricant composition comprising a major amount of a mineral lubricating oil and a minor amount, from 0.1 to 10.0 per cent by weight on the mineral lubricating oil,- of a salt having the formula:

o on on CHUCHi-OSO a a 1i R wherein R is the tetramethylbutyl radical and M is a divalent metal.

19. The composition of claim 18, wherein M is calcium.

20. The composition of claim 18, wherein M is barium.

21. The composition of claim 18, wherein M is tin.

22. The process which comprises condensing at a temperature not greater than 275 F. in a mineral lubricating oil one mol of a divalent metal salt of a phenol having a para alkyl substituent of from 4 to 12 carbon atoms, two mols of formaldehyde, and one mol of a phenol sulfide obtained by reacting at a temperature ranging from room temperature to 350 F. two mols of a phenol having a para alkyl substituent of from 4 to 12 carbon atoms with one mol of sulfur di- 10 chloride, ma recovering in solution in Bald min- REFERENCES CITED em lubricating on 9' salt the formula: The following references arev of record in the M file of this patent: 9 UNITED STATES PATENTS on 5 Number Name Date 1,966,050 Sloane July 10, 1934 2,174,248 Mikeska. Sept. 26, 1939 2,346,826 Cook Apr. 18,1944 10 2,352,435 Hoeflelman June 27, 1944 wh r in R, is an alkyl radical having Irom 4 to 2326389 Mikeska 12 carbon atoms and M is a divalent metal 2362293 McNab 2,409,687 Rogers Oct. 22, 1943 2,415,833 Mikeska. Feb. 18, 194':

15 2,420,893 McNab May 20, 184':

2,425,824 Peters Aug. 19, 1947 

